1. Field of Invention
This invention relates to protective apparatus for use by surgeons, dentists, and associated personnel during operations, and, more particularly, to such apparatus used for maintaining sterile operating conditions outside the apparatus while protecting the individual wearing the apparatus from coming into contact with splattered blood and tissue during orthopedic procedures.
2. Description of the Related Art
Fully covering protective garments, including a face shield and cloth covering the head and shoulders, are becoming increasingly common in operating rooms, particularly to protect the individual wearing the garment while providing sterile conditions for the operation outside the garment.
As reported in Health Devices, April, 1996, Vol. 25, No. 4, pp. 116-145, a surgical helmet system, in the form of either a loose-fitting hood or a hood combined with an integral gown, called a toga system, has been used particularly during orthopedic procedures to decrease the risk to the patient of deep wound infection by keeping skin and other particles from the surgeon""s face from falling into an open surgical site. Such a system has also been used to protect the surgical staff from infections blood splashes and from potentially infections aerosols generated by power tools during orthopedic procedures. This aspect of the use of such equipment provides particular protection against infection by the human immunodeficiency virus (HIV), by tuverculosis, and by the hepatitis C (HCV) virus.
Within a typical surgical helmet system, the helmet is an open framework molded from a thermoplastic resin, together with a structure forming an airpath extending from a location adjacent the rear of the wearer""s head to a location adjacent the wearer""s forehead. This structure includes an electric motor driven by a rechargeable battery fastened to a strap extending. An example of this type of helmet is described in U.S. Pat. No. 5,592,936 to Thomas, Jr., et al, which particularly discloses an air filtration system filtering air both entering and exiting the helmet area.
A typical surgical helmet system, as worn during an operating procedure, also includes a hood having a clear face shield, with the remainder of the hood being fashioned from a fabric material having an aperture to which the clear face shield is adhesively attached. The helmet and the hood are separate subsystems, which are not placed together until they are placed on the individual who is to wear them. After the procedure is completed, the hood is disposed, while the helmet will by used many more times.
A first problem with this type of surgical helmet system arises from the fact that the helmet is reused. Since it is generally used by a number of individuals, and since it fits closely around the head and face, the helmet itself may pass an infection from one wearer to another.
A second problem with this type of surgical helmet system arises from the fact that the helmet and hood are typically separate subsystems, with no particular provisions being made for the movement of air into and out of the hood. The hood is simply worn over the helmet, so that substantial portions of the air moving within the hood is allowed to recirculate, with levels of carbon dioxide rising within the hood due to the respiration on the wearer.
Marc H. Rubman, Mark G. Siegel, Alan S. Echt, G. Edward Burroughs, and Steven W. Lenhart, in a paper entitled xe2x80x9cLevels of Carbon Dioxide in Helmet Systems
Used during Orthopaedic Operations,xe2x80x9d published in The Journal of Bone and Joint Surgery, Incorporated, Vol. 80A, No. 9, September 1998, pp. 1264-1269, describe the results of an investigation in which levels of carbon monoxide were measured in four helmet systems from three different manufacturers. Three of these units failed to meet the OSHA-recommended limits of 5000 ppm for exposure to carbon dioxide. The fourth unit met these limits but still had levels of carbon dioxide within the helmet which were more than 1000 per cent greater than the ambient levels in air. The systems tested included a self-contained unit with integrated blowers and a helmet with a separate external blower connected by hoses. The subjects wore operative scrub suits and standard operating-room gowns over the helmet hoods as recommended by the manufacturers. One-piece combination face shields and gowns, called togas, were not used.
In this test, the highest concentrations of carbon dioxide were found in systems that used both inflow and exhaust blowers. The question of whether the helmet was self-contained or fitted with an external blower was not found to have a significant influence on the concentration of carbon dioxide. A configuration with an external blower having four ports was found to provide a lower concentration of carbon dioxide that a system using two ports with the same external blower. The most important design factor affecting the concentration of carbon dioxide was found to be the airflow pattern, with concentrations of carbon dioxide being significantly lower in systems having a inflow blowers only than such concentrations in systems having both inflow and exhaust blowers.
Thus, what is needed is a surgical protection system having a hood with a face shield and an air handling subsystem built together in a manner allowing the placement of a port extending into the ventilation system from an aperture in the hood. It is further desirable that such a surgical protection system would be low enough in cost to allow the disposal of the entire system, as opposed to the subsequent reuse of an internal helmet.
A number of other patents describe methods for providing protective covering and for ventilation without addressing the use of a port extending into the ventilation system through an external port in the hood, and without addressing a need for a hood and ventilation system which can realistically be provided together and discarded together after a single use.
For example, U.S. Pat. No. 5,558,153 to Ignon et al. describes a surgical gown adapted to be operatively disposed to substantially cover a surgeon wearing a ventilator having a waist-mounted power unit, a waist section, and a shoulder section appropriately configure to cover analogous portions of the surgeon""s body. A ventilator section, disposed between the head section and the waist section when the gown is operatively disposed on the surgeon, defines tube channel to receive the tube of the ventilator. This ventilator section forms an enlargement which facilitates movement of the head of the surgeon without substantial restriction by the head section of the gown. An interior tie gathers a front section of the gown around the neck of the surgeon to isolate movement between the head section and the shoulder section. The front section of the gown is covered with a plastic laminate to render the gown impermeable to fluids emanating from the front of the surgeon.
U.S. Pat. No. 6,014,971 to Danish et al. describes a protective system coupled with a face cradle for supporting the face shield on the wearer""s head. The face shield and the wearer""s face substantially define a breathing zone charged by a battery-powered blower carried on the head cradle. A bag-like inlet filter element encompasses the blower to provide filtered air to the breathing zone, and an outlet filter element is operably associated with the face shield.
U.S. Pat. No. 5,283,914 to James describes a protective helmet incorporating a visor retractable therewithin, a fan for providing filtered airflow through a duct within a shell to the visor, and ear protectors mounted substantially within the profile of the shell.
U.S. Pat. No. 4,752,974 to Haino describes an air-feed type protective helmet to which a face shield is rotatably mounted for movement between a lower use position and an upper non-use position. In order to feed clean air to a space provided between the wearer""s face and the face shield, a front visor portion is provided, forming a channel which extends between lateral sides of the helmet. An air outlet extends along a lower surface of the channel. An air pipe connector, in fluid communication with the air passage, is located on a lateral side of the helmet. A source of clean air can be connected to the air pipe connection.
U.S. Pat. No. 5,937,445 to Ravo et al. describes a one-piece surgical shield and cap including a substantially planar blank with an eye opening formed therethrough. Straps are attached to the side edges of the blank for connecting the one-piece surgical shield and cap to the user. The upper portion of the blank above the eye opening forms the cap portion, and the lower portion of the blank below the eye opening forms the shield portion. Elastic bands may be provided, surrounding the eye opening to further secure the one piece surgical shield and cap to the user.
U.S. Pat. No. 4,986,282 to Stackhouse et al. describes a face shield system pivotally mounted on an adjustable carrier having straps extending around and above the head.
According to a first aspect of the present invention, there is provided apparatus forming a protective barrier between a face and head of a wearer of the apparatus and a surgical environment. The apparatus includes a face shield and a head covering. The face shield is formed as a transparent tube, including a top edge, being formed to extend across the face and around a portion of the head. The head covering extends across the top edge of the face shield and downward around the face shield. The head covering includes a viewing aperture formed to extend across the face, and is adhesively attached to the face shield around the viewing aperture.